[Amazon’s] forthcoming persistent storage feature will give you the ability to create reliable, persistent storage volumes for use with EC2. Once created, these volumes will be part of your account and will have a lifetime independent of any particular EC2 instance.

With this much storage, you can imagine filesystems in which files are never deleted and files are never rewritten. The filesystem never forgets. Such systems could be much more reliable than the systems we use today which are based on the assumption that storage is a constrained resource.